US3746892A - Output voltage regulation system - Google Patents

Output voltage regulation system Download PDF

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Publication number
US3746892A
US3746892A US00134971A US3746892DA US3746892A US 3746892 A US3746892 A US 3746892A US 00134971 A US00134971 A US 00134971A US 3746892D A US3746892D A US 3746892DA US 3746892 A US3746892 A US 3746892A
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United States
Prior art keywords
output voltage
regulation system
voltage
resistor
voltage regulation
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Expired - Lifetime
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US00134971A
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English (en)
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M Ogiso
T Taguchi
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Individual
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Individual
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B7/00—Control of exposure by setting shutters, diaphragms or filters, separately or conjointly
    • G03B7/08—Control effected solely on the basis of the response, to the intensity of the light received by the camera, of a built-in light-sensitive device
    • G03B7/081—Analogue circuits
    • G03B7/083—Analogue circuits for control of exposure time
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/28—Modifications for introducing a time delay before switching
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
    • H03K17/78—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled
    • H03K17/795—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled controlling bipolar transistors

Definitions

  • the present invention relates to an output voltage regulation system.
  • the conventional output voltage regulation systems and circuits disclosed in the above applications are found unsatisfactory because the change in resistance of a resistor in a charging circuit affects somewhat the output voltage. More specifically the Zener point of the Zener diode changes as the resistance of the photoconductive element changes so that the voltage charged across the capacitor changes accordingly. As a consequence the conventional voltage regulation systems and circuits are not suitable for use with the timers such as the automatic shutter speed control devices which must function with a higher degree of accuracy.
  • an output voltage regulation system of the present invention is characterized in that a voltage divided by a bleeder resistor is applied to one input terminal of a difference amplifier as one input voltage; a unidirectinal feedback path is provided between a point at which the other input voltage to be applied to the other input terminal of the difference amplifier is derived and a point (the output terminal of the difference amplifier) at which the output voltage of the difference amplifier is derived so that the other input voltage may derive the stabilized output voltage; and the other input voltage is derived through the charging or discharging ofa time constant circuit comprising a variable resistor and a capacitor.
  • FIG. 1 is a circuit diagram of an automatic exposure control device incorporating a prior art outputvoltage regulation system
  • FIG. 2 is a view illustrating various waveforms of the output voltages derived in the circuit shown in FIG. 1;
  • FIG. 3 is a view illustrating various waveforms of the output voltages produced by the output voltage regulation system in accordance with the present invention
  • FIGS. 4, 5, 6 and 7 are circuit diagrams of several preferred embodiments of the present invention.
  • FIGS. 8 and 9 are circuit diagrams of automatic exposure control devices incorporating the output voltage regulation systems in accordance with the present invention.
  • A denotes a control circuit including a shutter and an aperture disphragm or blade assembly; E, a power source; SM, a main switch; Re and R resistors; C, a capacitor; Dz, a Zener diode; and S and S switches.
  • E a power source
  • SM a main switch
  • Re and R resistors a main switch
  • C a capacitor
  • Dz a Zener diode
  • S and S switches switches.
  • an appropriate aperture stop may be determined during this charging process and after the appropriate aperture stop has been determined, the switch S is switched to the fixed contact b, thereby opening the shutter. Then the capacitor C is discharged with a time constant depending upon the capacitor C and the resistor R,,. In this case it is seen that an appropriate shutter speed may be determined in the control circuit A in response to this discharge.
  • the potential V at the junction D when the capacitor C is charged is plotted against time T, where T 0 when the start switch S is closed, with the resistor R as a parameter.
  • E is the voltage of the power source E; R R R and V,,, V,, V,, It is seen that the potential at D changes as the resistor R changes so that the prior art circuit is not expected to function with a higher degree of accuracy in regulating or stabilizing the output voltage.
  • E designates a power source; S a main switch; R resistor; C, a capacitor; D a constant-voltage element such as a Zener diode; R,,, R a fixed and variable resistors; R R and R resistors; T and T transistors constituting a difference amplifier; D a diode for providing a unidirectional feedback path; and P, and P potentiometers.
  • the resistor R represents a photoconductive element as shown in FIG. 5 and the resistor PTr represents a phototransistor as shown in FIG. 6.
  • the resistor in FIG. 7 represents a combination of a photodiode PD and a transistor T so that the charging time constant may be dependent on the impedance of the transistor as shown in FIG. 7.
  • the equivalent impedance between the collector and emitter of the phototransistor PTr changes in response to the intensity of light incident thereupon so that the charging time of the capacitor C changes accordingly.
  • a voltage divided by the resistor R and the Zener diode D in turn is divided by the potentiometer P and applied to the base of the transistor T and the potential V at the point D when the capacitor C is charged is applied to the base of the transistor T, to control it.
  • the transistors T and T constitute a difference amplifier, the transistor T remains turned off until the potential V at the point D reaches a predetermined charged voltage V,,, whereeas the transistor T remains turned on.
  • the potential V reaches V
  • the transsistor T is turned on, while the transistor T remains on.
  • the diode D serves to supply current so that the capacitor C will not be charged with the current passing through the resistor R,.
  • the charging resistor R is provided independently of the discharging resistor R whereas in the embodiment shown in FIG. 9, one photoconductive element R is used as a common charging and discharging resistor.
  • the diode D may be eliminated by an arrangement in which a switch S closes either contacts a or b in response to the actuation of the switch S
  • An aperture stop is designated by F and the potentiometer is set to an appropriate value depending upon the sensitivity or speed of a film used.
  • Reference characters T and T designate transistors constituting a Schmitt circuit; T a power transistor; R R resistors; R,, an adjustment resistor; and M, and M magnets.
  • the magnet M serves to set an aperture to a predetermined stop while the magnet M serves to open and close the shutter.
  • the shutter is opened while the switch S, is switched from the fixed contact a to the fixed contact b, whereby the measurement of a shutter speed or a time interval after the shutter is opened is started.
  • the capacitor C is discharged through the photoconductive element R and when the potential at the point D reaches a predetermined level, the Schmitt circuit triggers again to energize the magnet M to close the shutter.
  • the automatic exposure control device is reset as shown in FIG. 9 as in the case of the circuits shown in FIGS. 3 and 8.
  • An output voltage regulation system adapted to apply a voltage divided by a bleeder resistor to one input terminal of a difference amplifier as one input voltage, a unidirectional feedback path being provided between a first point at which the other input voltage of said difference amplifier is derived and a second point at which the output voltage of said difference amplifier is derived, said feedback path being adapted to cause a flow of current from said first point to said second point only when the voltage across said other input is higher than the output voltage of said difference amplifier so that said other input voltage may derive the stabilized output voltage, and the said other input voltage being derived through the charging or discharging of a time constant circuit comprising a variable resistor and a capacitor.
  • variable resistance means comprises a combination of a photodiode (FIG. 7 PD) and a transistor (FIG. 7 T).
  • variable resistor in said time constant circuit is a photoconductive element.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Shutters For Cameras (AREA)
  • Exposure Control For Cameras (AREA)
  • Indication In Cameras, And Counting Of Exposures (AREA)
  • Control Of Electrical Variables (AREA)
  • Measurement Of Predetermined Time Intervals (AREA)
US00134971A 1970-04-24 1971-04-19 Output voltage regulation system Expired - Lifetime US3746892A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45035186A JPS5026732B1 (enrdf_load_stackoverflow) 1970-04-24 1970-04-24

Publications (1)

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US3746892A true US3746892A (en) 1973-07-17

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US00134971A Expired - Lifetime US3746892A (en) 1970-04-24 1971-04-19 Output voltage regulation system

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US (1) US3746892A (enrdf_load_stackoverflow)
JP (1) JPS5026732B1 (enrdf_load_stackoverflow)
DE (1) DE2119989C3 (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3886380A (en) * 1973-01-12 1975-05-27 Hitachi Ltd Gain control circuit
US3909702A (en) * 1973-12-26 1975-09-30 Ibm Switching voltage regulator with optical coupling
US4015145A (en) * 1975-09-19 1977-03-29 Ncr Corporation Voltage compensated timing circuit
US4075623A (en) * 1975-06-26 1978-02-21 Kabushiki Kaisha Suwa Seikosha Reference voltage circuit
US4302653A (en) * 1980-04-02 1981-11-24 Weltronic Company Method and apparatus for monitoring and controlling a resistance welding operation
US4748350A (en) * 1980-12-20 1988-05-31 Fujitsu Limited Emitter-coupled logic circuit

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5394023U (enrdf_load_stackoverflow) * 1976-12-29 1978-08-01
JPS5660179A (en) * 1979-10-22 1981-05-23 Yagi Antenna Co Ltd Coupler between interphone and television signal transmitter
GB8411074D0 (en) * 1984-05-01 1984-06-06 Ae Plc Reinforced pistons

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3246170A (en) * 1962-09-17 1966-04-12 Hallicrafters Co Sweep and function generator employing difference amplifier controlling varaible reactor
US3364441A (en) * 1966-03-07 1968-01-16 Elastic Stop Nut Corp Low frequency transistor relaxation oscillator
US3381212A (en) * 1965-11-15 1968-04-30 Alnor Instr Co Voltage regulator with proportional control

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3246170A (en) * 1962-09-17 1966-04-12 Hallicrafters Co Sweep and function generator employing difference amplifier controlling varaible reactor
US3381212A (en) * 1965-11-15 1968-04-30 Alnor Instr Co Voltage regulator with proportional control
US3364441A (en) * 1966-03-07 1968-01-16 Elastic Stop Nut Corp Low frequency transistor relaxation oscillator

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3886380A (en) * 1973-01-12 1975-05-27 Hitachi Ltd Gain control circuit
US3909702A (en) * 1973-12-26 1975-09-30 Ibm Switching voltage regulator with optical coupling
US4075623A (en) * 1975-06-26 1978-02-21 Kabushiki Kaisha Suwa Seikosha Reference voltage circuit
US4015145A (en) * 1975-09-19 1977-03-29 Ncr Corporation Voltage compensated timing circuit
US4302653A (en) * 1980-04-02 1981-11-24 Weltronic Company Method and apparatus for monitoring and controlling a resistance welding operation
US4748350A (en) * 1980-12-20 1988-05-31 Fujitsu Limited Emitter-coupled logic circuit

Also Published As

Publication number Publication date
DE2119989B2 (enrdf_load_stackoverflow) 1975-04-03
DE2119989A1 (de) 1971-11-11
JPS5026732B1 (enrdf_load_stackoverflow) 1975-09-03
DE2119989C3 (de) 1975-11-27

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